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Fenolne kisline

Fenolne kisline. Rdeča vina: 100-200 mg/L Bela vina: 10-20 mg/L. Fenolne kisline v grozdju. Benzojske kisline Esterozidi Estri (npr. elagi tanini) V peškah (npr. galna kislina) V vinih (tudi iz lesa) Cimetne kisline V vakuolah (meso in kožice)

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Fenolne kisline

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  1. Fenolnekisline • Rdeča vina: 100-200 mg/L • Bela vina: 10-20 mg/L

  2. Fenolnekisline v grozdju • Benzojske kisline • Esterozidi • Estri (npr. elagi tanini) • V peškah (npr. galna kislina) • V vinih (tudi iz lesa) • Cimetne kisline • V vakuolah (meso in kožice) • Eterozidi z glukozo (p-kumarna kislina) • Estri z H2T (kofeinska kislina) • Hydroxycinnamyltartaric acids (ICT) • Substrates of PPO • Acylated anthocyanins

  3. trans-resveratrol V kožicah Odziv na bolezni Francoski paradox Polimerizacija (viniferini) Stilbenes

  4. C6-C3-C6 skelet Flavonoidi

  5. Biosintezaflavonoidov

  6. Rumeni pigmenti V grozdju: 3 ali 7 glukozidi (Rha) V epidermisu vakuol V belem in rdečem grozdju Miricetin samo v rdečem V vinih: 20-30 mg/L (aglikoni) Flavoni

  7. Rdeči pigmenti, zelo razširjeni v naravi (sadje, rastline) V grozdju: acilirani glukozidi (razen pri MP) Locirani v celicah kožic Večinoma vezani z drugimi spojinami (kopigmentacija) Antociani

  8. Anthocyanidin anthocyanin acylated anthocyanin Antocianini

  9. Resonance Reaktivnostantocianov • Izmenjava naboja • barva molekule

  10. Anthocianini & pH pH 3 pH 7-8 pH 3,2-3,5 pH > 11 At pH 3, only the 42% of anthocyanins is in colored form (flavilium cation or quinonic base); this percentage decrease at 20% at pH 4

  11. Substitucija na B obroču Glucosylation and acylation shift barve proti oranžni (ipsochromic shift) Antocianini & barva

  12. Kopigmentacija • Barva antocianov v naravnih matriksih in v modelnih raztopinah • Kompleksi-reakcije med pigmenti in brezbarvnimi sestavinami (kopigmenti) • Fenolne kisline, flavanoli, flavoni… • Hiperkromični in bathocrhomic shift v VIS spektra • Steric stabilizacija molekule • Ekstremna variabilnost v barvi antocianov v naravi

  13. Kopigmentacijskimehanizem • Hydrogen bonds (Osawa, 1982) • Boultonov model (2001) • Aggregates originated by superimposition of planar sheets • Clockwise or counterclockwise helix, depending on pH • π-π (hydrophobic) interactions between benzene rings of anthocyanins and copigments • π-π interaction can be made also between only anthocyanins (auto-association)

  14. Antocianini & SO2 • Faktorji, ki vplivajo na reakcijo • pH in disociacijsko ravnotežje • Acetaldehid (MeCHO) (vezava SO2) • Tanini (stabilizacija antocianov)

  15. Only on free forms Anthocianini breakdown reactionsTermalnadegradacija/razgradnja 1

  16. Even on glycosides Anthocyanins breakdown reactionsThermal degradation 2

  17. Maceration T and extraction (Ribéreau-Gayon et al., 1970) Anthocyanins thermal degradation • T > 20 °C • Storage and maceration

  18. Razgradnereakcijeantocianovoksidativnarazgradnja • Polimerizacija s kinoni in semikinoni • Razpad/razgradnja heterocikla (benzojska ksl.) • Malvidin stabilnejši od cianidina • Najverjetnejši vpliv obojega: T and O2

  19. Anthocyanins breakdown • Pomen v praksi. •  Spremembe v barvi • Izguba na intenziteti barve • Sprememba barve proti rumenim odtenkom, povečanje “tona” barve CI = DO 420 nm + DO 520 nm + DO 620 nm Hue = DO 420 nm / DO 520 nm

  20. Enološkaevolucijaantocianov • 200 - 2.500 mg/L v grozdju • (monoglukozidi in acilirani) • Izlužljivost 50-60 %  200 - 1.500 mg/L v vinu • Prevladuje malvidin (50-90 %) • Razgradnja in oksidacija med zorenjem • Reakcije s tanini •  Starejša vina: 0-50 mg/L • zelo malo v prosti obliki • večinoma monoglukozidi

  21. 3-flavanoli 3,4-flavandioli Kondenziranitanini Flavanoli

  22. Flavanoliavan-3-ols (catechns) • V grozdnih kožicah in peškah • Estri galne kisline

  23. Proantocianidini (izantocianidinov s segrevanjem v kislemokolju) Taninigrozdja in vina V grozdju: v polimeriziraniobliki Flavan-3,4-diols (leucoanthocyanes)

  24. Procianidin B Ribéreau-Gayon et al., 1998

  25. Reaktivnostprocianidinov

  26. Polimerniprocianidini Ribéreau-Gayon et al., 1998

  27. Tanini • MW 500 – 3000 • Precipitation of gelatin and proteins, formation of blue-dark precipitates by reaction with ferric salts • Grozdni tanini : kondenzirani tanini (polimeri flavanolov) • Celice kožic - tri skupine taninov • Prosti v soku vakuol • Granular form (internal layers) • Big clusters (superficial layers) • Vezani na tonoplaste (interakcije s proteini) • Vezani na celične stene (interakcije s polisaharidi) • Tanini pešk: • Manj kompleksni in polimerizirani • Bolj reaktivni in astringentni

  28. Reaktivnosttaninov • Against proteins • Astringency Ribéreau-Gayon et al., 1998

  29. Dovzetnost polifenolov za oksidacijo Oksidacijapolifenolov

  30. Redox ravnotežje v vinu Raztopljeni kisik Težke kovine (Cu2+; Fe3+) Fenolne spojine Peroksidi in prosti radikali Fenolne spojine Žveplov dioksid Askorbinska kislina glutation OKSIDATIVNO OKOLJE REDUKTIVNO OKOLJE

  31. To je spremenljivka povezana z t.i. redoks stanjem v mediju, torej s koncentracijo oksidativnih in reduktivnih komponet v raztopini Redox potencial Ribéreau-Gayon et al., 1998

  32. Redox potential Ribéreau-Gayon et al., 1998

  33. White wines AF: alcoholic fermentation Red wines AF: alcoholic fermentation MLF: malolactic fermentation Changes in Eh during winemaking (Vivas e Glories, 1995) Ribéreau-Gayon et al., 1998

  34. O2 dissolution • Pretoki in zračenje • Skupna kapaciteta porabe kisika • Bela vina: 80 mg/L • Rdeča vina: 800 mg/L

  35. O2 dissolution Ribéreau-Gayon et al., 1998

  36. O2 solubilization during the main technological operations(Vivas, 1997)

  37. Chemical oxidation • Directly electroactive substances • Fe2+/Fe3+; Cu+/Cu2+ • Activation of O2 • Formation of peroxides (ROO•) and superoxides (•O2-) • Weakly electroactive substances • Conjugated dienols • They react with ROO• e •O2- • Radical polymerization • Formation of acetaldehyde from EtOH (aroma modifications) • Formation of quinones from polyphenols • Sensory effects • Color, aroma, taste

  38. Oxidative polymerization Direct intervention of O2 (Fe3+ e Cu2+) Ribéreau-Gayon et al., 2006

  39. Indirektnapolimerizacija • Reakcije z aldehidi (A obroč) • MeCHO from oxidation of EtOH

  40. Evolution of tannins • 1-4 g/L v vinih ob koncu AF • Direktna in via acetaldehid (indirektna) polimerizacija • Povečanje kompleksnosti • Oksidativni razpad/razgradnja • Čiščenje • Reakcije z antociani • Stabilnost barve

  41. Stability of anthocyanins and tannins • Čisti antociani zelo nestabilni v raztopini (vinu) • Čisti tanini slabo stabilni v raztopini (vinu) • Mešana raztopina s tanini in antociani Mixed : večja stabilnost

  42. KondenzacijskereakcijeTanini + antociani • Direktna kondenzacija • V steklenici • V nerjavnih cisternah • Indirektna (MeCHO-mediated) kondenzacija • Zorenje v sodih

  43. Ribéreau-Gayon et al., 1998 Bottle Reducing environment T-A kondenzacija

  44. Stainless steel vats O2 – after a racking A-T condensation Ribéreau-Gayon et al., 1998

  45. Direktnakondenzacija • Dependent on the T/A ratio; it is max. for a 1:10 ratio • Low tannin level: anthocyanins are easily degraded • High tannin level: tannin tend to self-polymerize without involving anthocyanins

  46. Ribéreau-Gayon et al., 2006 Indirektnakondenzacija

  47. Indirektnakondenzacija • Increase of CI and shift toward mauve hues • Importance of T/A ratio; good stabilization for values of 4 • Anthocyanins in polymerized forms: more stable as regards the loss in color (hydration and sulfiting), toward oxidation and thermal breakdown • Temperature and O2 (e.g. microox) improve condensation; too high levels lead to pigments breakdown • Acid pH favors condensation • SO2 diminution of available MeCHO • Enološki tanini in lesni tanini improve the formation of MeCHO from EtOH during aging

  48. Ideal situation Ravnotežje med between antociani in tanini • Phenolic ripeness Ribéreau-Gayon et al., 1998

  49. Real case Equilibrium between A & T Ribéreau-Gayon et al., 1998

  50. Effect of extraction technologies

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